Android Studio, Java Buffered Procol. Problem of recording data

I have a project in which I created a table with a series of TextViews, TextView with PopUpMenu and EditText, dynamically with the automatic filling of the data of a document.
The problem comes from the moment when, once I wrote something in EditText and selected an option in PopUpMenu that replaces what I wrote before, I do not know how to save it so that, the next Once I open the project, I open the table. with the new data.

A channel with (name, frequency, polarity …) with their respective values ​​in the table.
Using the EditText where these data are located, modify all or part of their values.
Now I need to know how to save the new data in the document so that when I open it again, I get the new data, not the old ones.
thank you so much